Consider the following statements regarding tensile test diagrams for carbon steels with varying carbon contents:
As the carbon content increases
1. the ultimate strength of steel decreases
2. the elongation before fracture increases
3. the ductility of the metal decreases
4. the ultimate strength increases
Which of these statements are correct?
Carbon has the maximum influence on the mechanical properties of steel. Iron-carbon alloys containing up to 2 per cent carbon are called carbon steel while those having more than 2% are called cast steel. With increase in carbon the tensile strength of steel increases but the ductility falls.
The effective flange area in tension of a plate girder is equal to
where Af is the area of each flange and Aw is the web area.
Effective flange area =
Net area of the flange =
The order of elongation which a specimen of mild steel undergoes before fracture is
For mild steel
(i) Proportional limit (190 - 220) N/mm2
(ii) Yield strength (230 - 250) N/mm2
(iii) Ultimate strength (410 - 530) N/mm2
(iv) Fracture strength (250 - 300) N/mm2
(v) Elongation at fracture (23 - 35)% Thus the order of elongation is 10%
A plate used for connecting two or more structural members intersecting each other is termed as
Base plates are provided to distribute the load of a column on greater area.
Which one of the following stresses is independent of yield stress as a permissible stress for steel members?
Axial tensile stress = 0.6fy
Bearing stress = 0.75fy
Maximum shear stress = 0.45fy
Stress in slab base = 185 MPa for all type of steels.
An equal angle of area A has been attached to the support by means of a lug angle. If allowable stress in tension is f, what is the load carrying capacity of the member?
Strength of member = allowable tensile stress x
Net area of the angle
Net area = Gross Area - deduction for holes.
The effective length of an angle member in a riveted truss is equal to which one of the following?
where I is the centre to centre distance between the joints.
Steel of yield strength 400 MPa has been used in a structure. What is the value of the maximum allowable tensile strength?
Maximum allowable tensile strength
A steel plate is 300 mm wide and 10 mm thick. A rivet of nominal diameter 18 mm is driven. The net sectional area of the plate is
Net sectional area of the plate is given by,
Anet = (B - nd) x t
= [300-1 x (18 + 1.5)] x 10
= 2805 mm2
The capacity of a single ISA 100 x 100 x 10 mm as tension member connected by one leg only using 6 rivets of 20 mm diameter is
The allowable stress is 150 N/mm2
The net area of the tension member is given by,
The angle section is connected by one leg only.